The function of an isolation transformer

An isolation transformer, commonly known as a safety transformer, is generally used to isolate the impurities present in the mains electricity and to protect equipment. To use an isolation transformer, it is first necessary to understand China’s power supply system. In China, when supplying power to low-voltage users, a three-phase four-wire system is typically used, with the neutral wire being grounded. In simpler terms, the wires that reach residential homes consist of one phase wire (live wire) and another wire that is the neutral wire, which is at the same electrical potential as the ground. When a person touches a hot surface, current can flow through the body, creating a circuit with the ground and resulting in electric shock. Using an isolation transformer makes things safer, as the primary and secondary sides exchange energy through a magnetic field, with no physical connection between them. Even if a person comes into contact with a live object, since the person is at the same potential as the ground, the voltage at the live part remains low, preventing any risk of electric shock. For example, when a person gets an electric shock, it is usually the electricity from a conductor that flows through the body and into the ground. This electricity flows into the ground because the power supply equipment is electrically connected to the ground; without such a connection, a person would not suffer an electric shock. When using isolation transformers, two things need to be taken into account. 1: Neither end of the transformer’s secondary side should be grounded. 2: The human body must not touch both ends of the secondary side at the same time, otherwise there is a risk of electric shock.

An isolation transformer is a 1:1 transformer, and its secondary side is not connected to ground. Since it is not connected to ground, various types of noise are reduced, thereby minimizing interference.

Isolation transformers are usually used as control transformers, so their capacity is generally not very large!

An isolation transformer operates on the principle of electrical isolation; there is electrical separation between the primary winding and the secondary winding. Both the internal components of the secondary winding as well as the metal casing outside the transformer must be grounded, and the neutral wire also needs to be grounded, thereby forming a local TN grounding system

Isolation transformers serve to provide electrical isolation

Isolation transformers are designed primarily to provide a safe voltage; their secondary coil is not grounded to ensure safety.

Isolation refers to the electrical insulation between the primary and secondary windings of a transformer. The isolation of a transformer is the separation of the currents in the primary and secondary windings. There are many types of isolation. For transformers used at low voltages, insulation paint is typically applied to the outside of the metal windings, and then the primary and secondary windings are wound around an iron core to form a transformer. The wire used for the windings of this type of transformer is what many people call \"enamelled wire\". The reason is that insulating paint layer. At this point, the primary and secondary sides are insulated, that is, separated, by that layer of paint. 　　The principle of an isolation transformer is the same as that of a regular transformer. They all make use of the principle of electromagnetic induction. An isolation transformer generally refers to a 1:1 transformer. Because the secondary ones are not connected properly. There is no potential difference between any of the secondary wires and ground. Safe to use. It is commonly used as a power supply for repairs. Isolation transformers are not all 1:1 transformers. The power supply for control transformers and tube equipment is also an isolation transformer. Power supplies such as tube amplifiers, tube radios, oscilloscopes, and control transformers for lathes are all isolation transformers. For safe maintenance of color TVs, a 1:1 transformer is commonly used. Isolation transformers are widely used, and they are also employed in air conditioners. 　　Isolation transformers serve to isolate distributed systems; step-down transformers are typically used to reduce the incoming voltage. Any isolation transformer used for controllers must have sufficient power to handle its load, with the power rating usually expressed in volt-amps VA.

This post was last edited by zyz8438 on 2010-7-23 at 11:24. To understand why isolation transformers are used, one must first be familiar with China’s power supply system. When supplying power to low-voltage users, China’s system generally uses a three-phase four-wire system with the neutral wire grounded. In simpler terms, the wires that reach residential homes consist of one phase wire (live wire) and another wire that is the neutral wire, which is at the same potential as the ground. When a person touches a hot surface, current can flow through the body, forming a circuit with the ground and causing electric shock. Using an isolation transformer makes things safer, as energy is transferred between the primary and secondary sides through a magnetic field, without any physical connection. Even if a person touches a live object, the potential of that live part will be low due to the person being at the same potential as the ground, thus preventing electric shock. There are two points to note when using an isolation transformer. 1. Neither terminal of the transformer’s secondary side should be grounded. 2. The human body must not come into contact with both terminals of the secondary side at the same time, otherwise there is a risk of electric shock. Features of isolation transformers: At the AC power input side, if the third harmonics and interference signals in the power grid are severe, the use of isolation transformers can eliminate these third harmonics and reduce interference signals. The use of an isolation transformer allows for the creation of a new neutral line, thereby preventing abnormal operation of equipment due to issues with the grid’s neutral line. Current waveform distortions caused by nonlinear loads (such as third harmonics) can be isolated and thus do not contaminate the grid. Features of isolation transformers at the AC power output: they prevent current distortions caused by nonlinear loads from affecting the proper operation of the AC power supply and from contaminating the power grid, thereby serving to purify the power grid. Sampling is taken at the input of the isolation transformer, so that the distortion in the current of the nonlinear load does not affect the accuracy of the sampling, thereby obtaining a control signal that reflects the actual conditions. If the load is unbalanced, it does not affect the normal operation of the voltage regulator. Using a DC/DC converter to eliminate high-frequency transient interference, RS-232/485 is one of the most widely used serial interfaces in PCs and the communications industry; it is defined as a single-ended standard that increases communication distance in low-speed serial communication. However, in practical circuit applications, RS-232/485 communication is often affected by interference and surges. There are many reasons for such interference, and to address it, it is necessary first to identify the cause of the interference and then take measures to resolve it. Generally, an isolation transformer is used to address interference issues. This approach is aimed at dealing with conductive interference coming from the power supply; it enables the blocking of most of such interference before it reaches the isolation transformer, and it also serves to transform the power supply voltage.

We have used 2 400 kVA isolation transformers here, allegedly to isolate the 380V power output from the diesel generator sets and convert it into 380V/220V power. May I ask if this approach and practice are indeed valid?